The role of small GTP-binding proteins in leukocyte function.

Recent progress in understanding the regulation of the phagocyte NADPH oxidase by the Rac GTP-binding protein(s) provides the first detailed glimpse into the mechanisms of leukocyte regulation by a small GTP-binding protein. Studies over the past year indicate that the activity of NADPH oxidase can be modulated by regulation of the GTP- versus GDP-bound state of Rac. Additional proteins of the Ras superfamily are likely to be involved in a variety of normal leukocyte functions.